ABSTRACT
BACKGROUND: Fibrous hamartoma of infancy (FHI) is a rare, benign, soft tissue mass that may be locally infiltrative. Primary excision is the mainstay of treatment; however, given the infiltrative nature, margin negativity can be difficult to achieve. The management of residual disease in the setting of positive margins after primary excision is not well described. METHODS: All patients undergoing FHI excision from 2012 to 2022 were included. Demographics, operative data, margin status, recurrence, and post-operative follow-up data were obtained via retrospective chart review. RESULTS: Nine patients were identified who underwent FHI excision. The median age at time of excision was 9 months (IQR 16). Seven (78%) were male, and the majority (78%) were white. Seven (78%) underwent preoperative imaging via ultrasound or MRI, and 4 (44%) had a preoperative biopsy to confirm diagnosis. Common locations included upper extremity (n = 4, 44%) and lower extremity/inguinal region (n = 4, 44%). Six patients (67%) had positive margins on pathology - 3 (33%) on the upper extremity, 2 (22%) on the lower extremity/inguinal region, and one (11%) on the flank. One patient (11%) had a local recurrence which did not undergo re-excision. CONCLUSIONS: FHI remains a rare diagnosis. There is a high margin positivity rate; however, local clinically significant mass recurrence remains uncommon. With low rates of clinically significant mass development coupled with the benign nature of disease, a "watch and wait" approach may be appropriate for patients with positive histologic margins after complete gross excision to avoid reoperation and need for complex reconstructions. LEVEL OF EVIDENCE: Level 4.